Spark-plug.



7 E M pm a a w w m 4 7 A f Z Um i 6 E. HOLZWORTH.

SPARK PLUG. APPLICATION FILED APR. 9, 1912.

WITNESSES turned, an internal shoulder 3 simple, mg lts parts arranged for ready separatlon.

J lllElD erases EDW'AR-D HGLZWORTH, OF ALLIANCE, OHIO.

SPARK-PLUG.

Specification of Letters Patent. Application filed April 9, 1912.

Patented Apr. 1%, laid. Serial No. 889,564.

To aZZ whom it may concern:

Be it known that I, EDWARD Honzwonrrnl a citizen of the United States, residing at Alliance, county of Stark, and State of Ohio, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs. .My object is to provide a spark plug of strong and durable construction havso that it m y be thoroughly cleaned when desired, and further, to provide a spark plug having electrodes constructed and arranged in a new manner, as also to provide packing, whereby certain parts of the plug are kept free from carbon and the reliability of the plug is insured.

One embodiment of the invention is set forth hereinafter and its novel features are recited in the appended claim.

In the accompanying drawings :F igure 1 is a side elevation; Fig. 2, a longitudinal section; Fig. 3, aside elevation of the stem and parts carried thereby; Fig. 41-, a section on line M, Fig. 3; and Fig. 5, a detail of a connector. 7

The spark plug has a metallic, tubular part provided with a screw-threaded end 1 adapted to afi'ord means of connection to the engine, a nut 2 by which the plug may be and an external screw threaded part 4:.

The insulating or porcelain stem 5 has a reduced bifurcated part 6 which passes centrally through the part 1, the shoulder 7 bearing against asbestos packing 8 interposed between said shoulder and the shoulder 3. This packing prevents the entrance of carbon to the interior of the plug beyond the shoulder 7. On the reduced part 9 which terminates in a shoulder'lO, is a nut 11 which is adapted to bear against the shoulder and to engage the screw threaded part a, thereby holding the stem 5 in position, the shoulders 7 and 10 preventing any endwise movement of the stem 5 Extending through the stem 5 is a rod 12 which has a cap 13 and binding nuts 14 at one end and at its opposite end is provided with an electrode 15 disposed at one side of the bifurcated part 6. Between the electrode 15 and the end part 6 is an asbestos or isinglass washer 16, the latter constituting a packing to prevent the entrance of carbon to the bore containing the rod 12. Extending through a bore in the porcelain stem 5 isa rod 17 which terminates in an electrode 18, disposed opposite the electrode 15 and at the other side of the bifurcated part 6. Between the electrode 18 and the end of the part 6 is an asbestos or isinglass washer 19. The bifurcated part 6 provides a clear spark gap and also facilitates of carbon from the electrodes. Therod 17 extends through shoulder 10 and is provided with a clamping nut 20 which is located in a cut out portion 21in the stem and is disposed against a piece of asbestos or isinglass 22 arranged in said out out part. The stem 17 passes through a metallic contact member 23 which is held by the clamping nut 20 in the-cut out part 2 1 of the steni. This contact member is preferably of copper and the part thereof "which overhangs the enlarged part of the stem bears against the interior wall of the screwthreaded part 4 thereby placing therod 17 in circuit with the engine frame.

The asbestos or isinglass washers or pieces prevent the accumulation of carbon on the bores through which the rods 12 and 17 pass and the provision of the asbestos or isinglass piece 22 further prevents the escape of any carbon which may have entry to the bore for the rod 17.

The parts may be readily separated for purposes of cleaning Having thus described my invent on, what I claim as new and desire to secure by Letters Patent, is

' In spark plug, the combination with an inner insulating stem having an enlarged shouldered part intermediate its ends, of an outer metallic two-part attaching member for securing the plug to the engine. said attaching member being engaged with the enlarged part of the stem, a terminal extendthe voiding ing through the stem end p rovided with an engaged with the two-pert attaching memelectrode, another terminal having an elecber,

shouldered portion of said enlarged part, "a clamping device fonholding the last trode and extending through the. enlarged In testimony whereof, I hereunto aflix my part .of the stem and emerging from the signature in presence of two witnesses. EDWARD HOLZWORTHL Witnesses:

PERRY C. WEAVER,

named terminal in position, and ,a, contact JAMES I. RIOKARD.

member held by the clamping device and Copies of this petnt may be obtained for five cents each, by addressing the Commissioner 0'1 Patents,

Washington, D. G. 

